It's probably a very good idea to have one air dasher because the skills are transferable among the dashers. I think you will like Captain Marvel and then choose any second character you like. Right now everyone is learning the game by themselves and exploring their duo so you have to hit the lab yourself and find your own synergy. The game is open enough to allow that.
I do like the sound of the bolded. I was listening to commentators in exhibitions, though, and they were talking about how the game seems more rushdown/offensive based than MvC3, so I don't know how a Chris + Hawkeye + Time Stone (something I was considering) team would balance out in the future.
But yeah, while everyone's figuring out their own styles right now, I guess the right answer for now is whatever feels the best to you.
Aren't you a grappler guy by trade? Have you tried Haggar and Nemesis? (the latter isn't really a grappler but it's a big boy) Depends on what you like in a character tbh.
As for team comp and synergy, I don't think you have to worry too much about it. Like maybe someone with a projectile/speedy who can get in and someone who can hit hard. But stones can offset some weaknesses so nbd right now.
I am not. I hate command grabs because of the associated risk. If you're thinking of my time in SFV, I picked up R. Mika for literally these two reasons, and them alone:
1. She says "I'll totally make this look cool!" and "I'll kick your ass!" as signature quotes.
2. Her V-Trigger was the most alike a puppet character.
Point 2 really draws me to the Soul Stone, actually.
Maybe at a lower level, synergy won't matter too much. But looking at the exhibitions, it's obvious that players need to find ways for the characters in their team to properly complement each other for things to work out. At first, I was thinking that a rushdown character and a zoning character would make for a balanced team. Guess I'll think about that more.